1. Field of the Invention
The present invention relates to stringed instruments and particularly to a stringed instrument having a body made of injection molded high density polystyrene foam with a foaming agent which is injection molded to be used by itself or injected around a wooden core, the wooden core having alignment holes for receiving pins on the mold thereby holding the core in place during the injection molding process or injected to form a top and bottom panel adhered together with a wooden core sandwiched therebetween, and to injection mold a metal reinforced neck.
2. Description of Related Art including information disclosed under 37 CFR 1.97 and 1.98
Desirable characteristics for stringed instruments, such as base viols, cellos, guitars, and violins, etc., include the provision of sharp, clear tones, and substantial resonance. Prior art guitars often do not produce such tones, and typically have resonance periods of only about 8 seconds.
U.S. Pat. No. 7,141,730, issued Nov. 28, 2006 to Wu, is for a method of producing electric guitar body without the costly and time-consuming process of wood-carving or other traditional woodworking technique. By creating the molds and injecting proper materials, present invention also achieves the 3-D artistic rendition of desired shape for an electric guitar body and at reduced weight than solid wood carving guitar body. Reinforcement wood pieces are added into the two respective molds, to provide structural strength.
U.S. Pat. No. 4,334,452, issued Jun. 15, 1982 to Morrison, III, illustrates a plastic body for a solid body musical instrument such as an electric guitar, which body consists of a plastic body molded in the shape of the musical instrument body and a structural support member of wood or other suitable material embedded within the plastic body. The structural support member has a profile shape which is substantially a reduced scale version of the profile shape of the body and is so dimensioned and positioned within the body that the thickness of plastic about the structural member at most points along the member is substantially minimized and the mass of plastic material on one side of the member is not substantially greater than the mass of plastic on the opposite side of the member. The body is adapted to have an electric pickup mounted thereon, the support member being exposed in the area thereof adjacent the pickup and the pickup being mounted in close proximity to the exposed portion of the member.
U.S. Pat. No. 6,359,208, issued Mar. 19, 2002 to Farnell, Jr., discloses a stringed musical instrument or guitar having a plastic foam body substantially covered by a shell of thermoplastic material, a wood base on the plastic foam body, a plurality of strings supported to extend above the wood base, and at least one electromagnetic pick-up at the base. Musical vibrations produced by strumming the strings are conducted via the plastic foam body and wood base are largely sensed by the electromagnetic pick-up.
U.S. Pat. No. 5,054,356, issued Oct. 8, 1991 to Farnell, Jr., indicates a guitar which has a hollow plastic body including spaced front and back panels, and a foam plastic core disposed between the panels, whereby upon vibration of the panels air trapped within the individual cells of the foam core are alternately pressurized and depressurized, thus to enhance the musical output of the guitar.
U.S. Pat. No. 6,686,522, issued Feb. 3, 2004 to Won, provides a musical instrument with a body made of polyurethane foam. Won relates a musical instrument having its entire body portion manufactured by molding the body with synthetic resin, in which said musical instrument is an electric guitar that has the entire body consisting of a base plate, a neck part connected to the base plate and a head part connected to the end of the said neck part to hang the strings, and in which the said entire body is made of polyurethane foam having specific gravity in the range of 0.3 to 0.9. In the polyurethane foam additional porous particles sizing average diameter from 1 to 50 .mu.m selected from a group comprising wood chips, silica or mixtures thereof may homogeneously be contained in an amount of 5 to 8% by weight. Furthermore, a piano, an exterior casing of amplifier and/or an exterior casing of electric guitar may also be made of polyurethane foam having specific gravity in the range of 0.3 to 0.9.
U.S. Pat. No. 6,683,236, issued Jan. 27, 2004 to Davis, shows a one piece composite guitar body. A body for a stringed instrument is provided comprising a front face and a back face and a continuous side face there around; and an exterior laminate, the exterior laminate being formed of a plurality of composite layers including an interior layer, the composite layers of the laminate also including at least one supplemental layer, each layer including strands enveloped in an associated polymeric binder, with each subsequent layer being in intimate contact with the next adjacent layer. Davis also mentions that if a solid body is desired such as used with electric guitars, the appropriate shape needs to be molded. Foam can then be injected into the cavity of the hollow shell and the part may be removed from the mold and finished using conventional methods.
U.S. Pat. No. 6,538,183, issued Mar. 25, 2003 to Verd, claims methods of construction for acoustic and electrically amplified stringed musical instruments. The invention further relates to acoustic and electrically amplified stringed musical instruments comprising fiber-reinforced resin composite materials, where the instruments are provided with a sound-damping interior coating. In another variation of the method of the invention, after the mold pieces are mated, a fast-curing foam is blown into the space between the top layers and bottom layers of resin-impregnated fiber cloth, to press them firmly against the mold surfaces. The foam-filled mold is then held at a curing temperature for a time sufficient to cure the fiber-reinforced composite material. After the curing is complete, some or all of the foam can be removed, as desired for optimal sound production. If the instrument is to be electrically amplified, it may be desirable to leave much of the polymerized foam intact.
U.S. Pat. No. 4,213,370, issued Jul. 22, 1980 to Jones, describes molded plastic guitars having a soundbox body which is a one piece plastic molding having an offset bottom concave-convex substantially parabolic sound reflector area joined by a reinforcing rib structure to the wall of the body. A top panel is mounted on a supporting and reinforcing frame attached to the upper edges of the body wall. A neck molded from lightweight plastic has lightweight metal reinforcement extending longitudinally therein. An attachment heel structure on the neck is received and secured in a complementary socket in the upper bout of the soundbox body. Tuning gear is housed in complementary bearing recesses formed complementally in a head panel on the neck and a head plate removably secured to the head panel, and providing bearing holes through which tuning posts extend for attachment of the tuning ends of the playing strings which extend therefrom over an adjustable nut and spaced over the finger board, and then across a sound hole bordered by a ring member locating a pick guard. Anchorage for the strings is provided by a bridge structure comprising a base member on which is mounted a pad carrying a saddle, the pad having means securing the bridge assembly in place on the top panel. Attached to the lower face of the top panel is a bracing structure comprising bars and ribs in a one piece molding together with the supporting and reinforcing frame and including an attachment pad underlying the bridge structure to which the bridge pad is attached.
U.S. Pat. No. 3,427,915, issued Feb. 18, 1969 to Mooney, puts forth an acoustic panel, particularly the front and back panels of a violin, which has three-ply sandwich construction with a strip of balsa or a rigid foam that can serve as a center ply between rigidifying outer plies. Mooney mentions the use of polystyrene foam.
U.S. Pat. No. 5,469,770, issued Nov. 28, 1995 to Taylor, concerns a distributed load soundboard apparatus for a stringed musical instrument which can be constructed of traditional tonewoods or from manmade materials such as carbon graphite, expanded polystyrene plastic rigid foam or other molded plastics, polyurethane or epoxy material compounds (mineral loaded or not) or even lightweight metals.
U.S. Pat. No. 6,933,428, issued Aug. 23, 2005 to Pedgley, is for acoustic devices, particularly musical instruments, having a soundboard formed from expanded polycarbonate having a foamed structure, methods of manufacture of same, and the use of specific soundboards in the manufacture of acoustic devices.
U.S. Pat. No. 4,290,336, issued Sep. 22, 1981 to Peavey, provides a guitar neck and body made from moldable materials such that the finished guitar may be made either solid, semi-solid, or substantially hollow, and wherein the structure further includes interconnection areas between the various components to provide a finished article which can be durable, require less manufacturing processes, while simultaneously providing performance characteristics at least comparable to conventional designs for guitars.
U.S. Pat. No. 4,185,534, issued Jan. 29, 1980 to Cove, shows the use of a foamed polymeric material in the fabrication of solid-bodied, stringed musical instruments with the preferred material being a homogeneous body of foamed polystyrene having a density of from about 0.5 to about 6 pounds per cubic feet. Since the neck assembly must of necessity have greater structural strength than the body, it is contemplated using a relatively simple disconnect mechanism for coupling same to the body. Although the essence of the invention lies in the fact that with the foamed solid body additional sounding amplification means are unnecessary, electrical amplification can optionally be added to said instruments.
U.S. Pat. No. 3,618,442, issued Nov. 9, 1971 to Kawakami, claims foamed materials of various synthetic resins for making vibrating plates of sound instruments, such as, piano or guitar. Such resins include polystyrene, polyvinylchloride and the like.
U.S. Pat. No. 4,313,362, issued Feb. 2, 1982 to Lieber, describes guitar construction. A body is provided having a rear panel and sides integrally formed of plastic, with a top panel secured across the upper sides, the body being connected to a neck, having a U-shaped cross section, and a peghead, integrally formed of plastic with the neck. A flat plastic panel is secured across the open side of the neck, for attachment of a fret board, and a reinforcement rod runs from the butt end of the body to the upper portions of the peghead. Plastic foam is shot within all interior portions of the body, neck and peghead.
U.S. Pat. No. 6,107,552, issued Aug. 22, 2000 to Coomar, discloses a stringed instrument soundboard including composite structure that includes first and second opposed layers of a stiffened graphite sheet material and a low-density foam core interposed between the first and second opposed layers.
U.S. Pat. No. 3,664,911, issued May 23, 1972 to Takabayashi, puts forth a diaphragm for sound instrument and method for producing same in which the diaphragm comprises an assembly of foamed granules of thermoplastic resin, binder layer surrounding the foamed granules and connecting them together to form an integral body of the diaphragm and a fibrous reinforcing material applied on at least one surface of said body and embedded in the binder to form a reinforcing layer. The diaphragm may be used as a sounding board of a guitar or a piano.
U.S. Pat. No. 4,188,850, issued Feb. 19, 1980 to Kaman, II, concerns a foamed plastic guitar construction. The guitar has a separate body and neck each made of a metallic frame combined with a mass of structural foamed plastic. A solid joint, involving metal to metal contact of the two frames, is provided between the body and the neck and is readily unmade to allow disassembly of the neck from the body for repair or replacement of either the body or the neck. The two frames provide a continuous metallic span from the nut to the bridge to inhibit bending under string tension and also to enhance sustain by reducing damping. The external surface of the neck and body plastic masses may be given a grain effect, color and finish causing such masses to closely simulate wood.
What is needed is a stringed musical instrument which produces superior tone, sustain and resonance and yet can be mass produced quickly and inexpensively.